package org.seckill.service.impl;

import org.seckill.dao.SeckillDao;
import org.seckill.dao.SuccessKilledDao;
import org.seckill.dto.Exposer;
import org.seckill.dto.SeckillExecution;
import org.seckill.entity.Seckill;
import org.seckill.entity.SuccessKilled;
import org.seckill.enums.SeckillStateEnum;
import org.seckill.exception.RepeatKillException;
import org.seckill.exception.SeckillClosedException;
import org.seckill.exception.SeckillException;
import org.seckill.service.SeckillService;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import org.springframework.util.DigestUtils;

import java.util.Date;
import java.util.List;

/**
 * Created by qqz on 2018/5/12.
 */

@Service
public class SeckillServiceImpl implements SeckillService
{
    private Logger logger = LoggerFactory.getLogger(this.getClass());

    @Autowired
    private SeckillDao seckillDao;

    @Autowired
    private SuccessKilledDao successKilledDao;

    // 盐值，用于混淆md5
    private final String salt = "anbsljfljsldfjlsdfj*&*@^*@lljlj@(@(#12123sdf))";

    @Override
    public List<Seckill> getSeckillList()
    {
        return seckillDao.queryAll(0, 4);
    }

    @Override
    public Seckill getById(long seckillId)
    {
        return seckillDao.queryById(seckillId);
    }

    @Override
    public Exposer exportSeckillUrl(long seckillId)
    {
        Seckill seckill = seckillDao.queryById(seckillId);
        if (null == seckill) {
            return new Exposer(false, seckillId);
        }

        Date startTime = seckill.getStartTime();
        Date endTime = seckill.getEndTime();

        Date nowTime = new Date();

        if (nowTime.getTime() < startTime.getTime() || nowTime.getTime() > endTime.getTime()) {
            return new Exposer(false, seckillId, nowTime.getTime(), startTime.getTime(), endTime.getTime());
        }

        String md5 = getMD5(seckillId);

        return new Exposer(true, md5, seckillId);
    }

    @Override
    @Transactional
    /**
     * 使用注解控制事务方法的优点：
     * 1：开发团队达成一致约定，明确标注事务方法的编程风格
     * 2：保证事务方法执行的时间尽可能短，不要穿插其他网络操作RPC/HTTP请求或者剥离到事务方法外部
     * 3：不是所有的方法都需要事务，如只有一条修改操作，只读操作不需要事务控制。
     */
    public SeckillExecution executeSeckill(long seckillId, long userPhone, String md5) throws SeckillException, RepeatKillException, SeckillClosedException
    {
        if (md5 == null || !md5.equals(getMD5(seckillId))) {
            throw new SeckillException("seckillid data rewrite");
        }

        //执行秒杀逻辑
        Date nowTime = new Date();

        try {
            int updateCount = seckillDao.reduceNumber(seckillId, nowTime);
            if (updateCount <= 0) {
                //没有更新记录
                throw new SeckillClosedException("seckill is closed");
            } else {
                //记录购买行为
                int insertCount = successKilledDao.insertSuccessKilled(seckillId, userPhone);
                //唯一：seckilId,userPhone
                if (insertCount <= 0) {
                    //重复秒杀
                    throw new RepeatKillException("seckill repeated");
                } else {
                    //秒杀成功
                    SuccessKilled successKilled = successKilledDao.queryByIdWithSeckill(seckillId, userPhone);
                    return new SeckillExecution(seckillId, SeckillStateEnum.SUCCESS, successKilled);
                }
            }
        } catch (SeckillClosedException e) {
            throw e;
        } catch (RepeatKillException e) {
            throw e;
        } catch (Exception e) {
            logger.error(e.getMessage(), e);
            //所有编译期异常转化为运行期异常
            throw new SeckillException("seckill inner error: " + e.getMessage());
        }
    }


    private String getMD5(long seckillid)
    {
        String base = seckillid + "/" + salt;
        String md5 = DigestUtils.md5DigestAsHex(base.getBytes());
        return md5;
    }
}
